Anatomy and Physiology 1 Chapter 1 Study Guide

Core Definitions

• Gross Anatomy: The study of structures that can be seen with the naked eye.

• Cells: The most basic building units of life. All living things are composed of cells.

• Homeostasis: The body's ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions.

  • Prefix homeo-: Means "similar" or "same".

Historical Figures in Anatomy

• Andreas Vesalius: Published the first atlas of anatomy.

Homeostatic Feedback Loops

• Negative Feedback:

  • Function: Keeps a physiological variable close to its set point.

  • Negative Feedback Loop Mechanism: The body senses a change and activates mechanisms to reverse that change.

  • Examples:

  • Thermostat: Regulates temperature around a set point.

  • Sweating: Cools the skin.

  • Shivering: Warms the muscles.

• Positive Feedback:

  • Function: Acts as a self-amplifying cycle that leads to greater change in the same direction. The feedback change is repeated, and the change produces more change.

  • Examples:

  • Childbirth:

    • During childbirth, the head of the fetus pushes against the cervix and stimulates its nerve endings.

    • The hormone oxytocin is secreted from the pituitary gland.

    • Oxytocin travels through the bloodstream to the uterus, stimulating it to contract.

    • The contracting uterus causes the head of the fetus to push on the cervix, repeating the cycle.

  • Fever:

    • During a fever, the body's metabolic rate increases.

    • The body produces heat even faster, which directly raises the body temperature.

Modalities of Medical Imaging

• Radiography (X-rays):

  • Mechanism: Penetrates tissues to darken photographic film. The denser the tissue, the whiter it appears on the film.

  • Primary Application: Bones are the densest tissue, so they appear whiter; therefore, X-rays are most commonly used to study bones and joints.

  • Secondary Application: Sometimes used to detect problems affecting soft tissues, such as internal organs.

• Radiopaque Substances:

  • Application: Substances that are injected or swallowed.

  • Function: Fills hollow structures like blood vessels or the intestinal tract to make them visible.

• Computer Tomography (CT Scan):

  • Mechanism: Utilizes low-intensity X-rays assisted with computer analysis.

  • Diagnostic Uses: Used to diagnose tumors, investigate internal bleeding, or check for other internal injuries or damage.

• Positron Emission Tomography (PET Scan):

  • Mechanism: Assesses the metabolic state of tissue and distinguishes tissues that are most active at any given moment.

  • Diagnostic Uses: Can evaluate organs and/or tissues for the presence of disease or other conditions.

• Magnetic Resonance Imaging (MRI):

  • Mechanism: Based on the alignment and realignment of hydrogen atoms with a magnetic field and radio waves. Measures the varying levels of energy given off to determine different tissues.

  • Diagnostic Uses: Mostly investigates or diagnoses conditions that affect soft tissue, such as tumors including cancer.

• Sonography:

  • Mechanism: High-frequency waves echo back from internal organs. These echoes are measured by a computer.

  • Diagnostic Uses: Used to learn about conditions that involve soft tissues, such as organs, glands, and blood vessels.